Distributed-leader-election service for a distributed computer system

Abstract

Embodiments of the present invention provide methods and systems for leadership allocation in a distributed computer system. In certain embodiments of the present invention, a leader-election-service process runs within each node of a distributed computer system, together cooperatively providing a distributed-leader-election service. The distributed-leader-election service employs a distributed consensus service to manage distributed state information related to roles and leadership allocation within a distributed computer system. Client processes within each node interface with the leader-election-service process of the node in order to assume leadership of particular roles within the distributed computer system. Leadership-allocation management is thus centralized, within each node. In alternative embodiments, the distributed-leader-election service may be implemented as a collection of library routines that run in the context of client processes.

Description

TECHNICAL FIELD OF THE INVENTION[0001]The present invention is related to distributed computing and, in particular, to a method and system for efficiently and robustly allocating leadership within a distributed computer system.BACKGROUND OF THE INVENTION[0002]In the early days of computing, computer systems were stand-alone devices accessed by computer users via input / output (“I / O”) peripheral components, including control-panel toggle switches, Hollerith-card readers, line printers, and eventually cathode-ray-tube (“CRT”) 24-line terminals and keyboards. When a user wished to carry out a computational task on more than one computer system, the user would manually transfer data between the computer systems via Hollerith cards, magnetic tape, and, later, removable magnetic-disk packs.[0003]With the advent of multi-tasking operating systems, computer scientists discovered and addressed the need for synchronizing access by multiple, concurrently executing tasks to individual resources,...

AI Technical Summary

Problems solved by technology

Although initial distributed computer systems were relatively loosely coupled, far more complex, tightly coupled distributed computer systems based on distributed operating systems and efficient, distributed computation models, have since been developed.

Tasks for which leaders need to be assigned are generally tasks that are not efficiently decomposed, iterative tasks with high, initial-iteration computational overheads, and tasks that require assembling complex sets of privileges and controls over resources.

However, relatively static leader assignment may lead to time-consuming and difficult leader-reassignment problems when a leader node fails or becomes incapable of carrying out those tasks required of the leader node.

Alternatively, all nodes can constantly contend for leader roles for tasks requiring a leader on an on-demand basis, but constant leader-role contention may be inefficient and may even lead to thrashing.

However, in more complex distributed computer systems, leadership may need to be allocated for multiple roles on a continuing basis, and leadership may need to be distributed among individual processes running on nodes within a distributed computer system.

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